getDnString example

if ('' !== $ldapBadge->getSearchDn() && '' !== $ldapBadge->getSearchPassword()) {
                    try {
                        $ldap->bind($ldapBadge->getSearchDn(), $ldapBadge->getSearchPassword());
                    } catch (InvalidCredentialsException) {
                        throw new InvalidSearchCredentialsException();
                    }
                } else {
                    throw new LogicException('Using the "query_string" config without using a "search_dn" and a "search_password" is not supported.');
                }
                $identifier = $ldap->escape($user->getUserIdentifier(), '', LdapInterface::ESCAPE_FILTER);
                $query = str_replace('{user_identifier}', $identifier, $ldapBadge->getQueryString());
                $result = $ldap->query($ldapBadge->getDnString(), $query)->execute();
                if (1 !== $result->count()) {
                    throw new BadCredentialsException('The presented user identifier is invalid.');
                }

                $dn = $result[0]->getDn();
            } else {
                $identifier = $ldap->escape($user->getUserIdentifier(), '', LdapInterface::ESCAPE_DN);
                $dn = str_replace('{user_identifier}', $identifier, $ldapBadge->getDnString());
            }

            $ldap->bind($dn, $presentedPassword);
        }